Oilseed commodities such as soybeans, sunflowers, and canola are processed into both an oil product and a meal product. Often an oil-processing plant will only process one oilseed type, for example, only soybeans or only sunflowers. In processing plants that process one seed type, incoming oilseed commodities are often stored together prior to processing. Historically, these practices were cost efficient because the plant would typically produce one product type.
There are processing plants that process more than one oilseed type, e.g., both soybeans and sunflowers. These plants are commonly referred to as "switch plants." Switch plants are typically large in scale, processing on the order of 2400 tons of seed per day. Switching from one commodity to another in a switch plant is a substantial undertaking that often requires ceasing oilseed processing altogether. During the down time, holding bins, conveyors, augers, processors and product holding areas are cleaned of the previous oilseed type that tends to "hang-up" in the processing equipment. Such cleaning steps are taken to minimize commodity commingling. Shutting down an entire processing plant is both time consuming and expensive.
Alternatively, a switch plant continues operating and simply starts processing the next oilseed type without taking cleaning steps to minimize commodity commingling. In this instance, processors simply accept the fact that for a certain amount of time following the switch, the oilseed products will contain a mixture of the previous and current oilseed type characteristics. The resulting commingled products are then sold at a reduced price. The commingled oilseed products are referred to as flush products, i.e., flush oil and flush meal. On average, conventional processing plants produce flush oilseed products equalling about 3.5% of the total oilseed product produced when switching from processing a first oilseed type to processing a second oilseed type. For example, if an average processing run was 72 hours long, the processing plant would produce products for about 2.5 hours after switching from the first oilseed type to the second oilseed type unless the processing plant was shut down and the first oilseed type was cleaned out from the processing equipment. Switching without a shut down can be cost effective when running large batches and limiting the number of times the plant switches.
Conventional oil extraction methods and equipment are designed to produce a fungible commodity, e.g., all soybean meals and soybean oils would be considered the same and could be substituted with another soybean meal or oil. An increasing number of farmers now grow specialty oilseed types, e.g., genetically modified oilseeds (GMO's) including corn, soybean, sunflower, and canola seed produced by transgenic plants. Specialty oilseeds have unique features that set them apart from traditional oilseeds. For example, a particular oilseed may produce seeds with increased concentrations of a desired oil component, or produce large quantities of a valuable nutrient or amino acid. When processed, these specialty oilseeds can produce unique end products that are referred to as identity preserved (IP) products. The oils and meal extracted from IP products can demand a higher price as long as product identity is preserved. In other words, identity preserved oilseed products are not fungible or interchangeable. As a result, there is a need for commercial-scale and cost-effective methods for processing oilseeds that produce IP products and for processing smaller batches of different commodities in the same plant.